1. Field of the Invention
The invention relates to the fabrication process of a semiconductor device, and more particularly, relates to the fabrication process of a contact window.
2. Description of the Related Art
As the density or integrated circuits is further increased by continuously shrinking the device dimensions, the line width, the contact area and the junction depth are continuously being miniaturized. When forming a contact window of a source/drain region, due to a reduction of the contact area, the demand for an accurate alignment is increased. The probability of a misalignment is also increased. In the process of etching the contact window, it is common that the boundary of the neighboring isolation structure of the source/drain region, such as a field oxide layer (FOX) or a shallow isolation trench (STI), is coincidentally removed, resulting in a leakage current.